Detection prevention and treatment of Papillomatous Digital Dermatitis

ABSTRACT

The present invention relates to the use of Serpens spp. bacteria or bacterin in compositions, such as vaccines, and methods for the detection, prevention and/or treatment of Papillomatous Digital Dermatitis in ruminants. The present invention also provides biologically pure Serpens spp. strain HBL-112, and biologically pure Serpens spp. strain HBL-112 bacterin.

The present application claims priority under 35 USC 119(e)(1) from our Provisional Application No. 60/022,915, filed Aug. 1, 1996.

FIELD OF THE INVENTION

The present invention relates to methods and compositions useful in the detection, prevention and/or treatment of papillomatous digital dermatitis in ruminants and to a novel strain of Serpens spp. bacteria useful for that purpose.

BACKGROUND OF THE INVENTION

Papillomatous Digital Dermatitis (PDD) is a chronic infectious and apparently contagious disease of the feet and/or lower legs of cattle. The disease is known by several common and scientific names including digital dermatitis, interdigital papillomatosis, digital papillomatosis, verrucous dermatitis, footwarts, hairy footwarts, hairy heelwarts, raspberry heel, strawberry foot disease and strawberry footrot. It has been identified as one of the most significant diseases facing the dairy industry today. The disease results in lameness which leads to economically significant reductions in milk production and concomitant declines in animal health such as body weight loss, and fertility. It is believed that the agent can be brought onto a dairy via introduction of new stock or formite transmission from hoof trimmers, dairy testers, muddy boots on veterinarians, etc. In dairies currently experiencing losses from the disease, it has been estimated that the cost in lost milk production, reproductive losses and increased culling averages at least $100 per day.

To date, only two control methods have shown promise: use of antibiotics topically (cleaning, curettage and bandaging each foot) or parenterally (problematic for reasons of milk withdrawal), and the use of bacteriocidal footbaths (antibiotics, formaldehyde, iodine, etc.). Although many lesions may respond well to antibiotics or footbaths containing antibacterial compounds, recurrences are known to occur and some evidence suggests development of antibiotic resistance. These approaches are labor intensive, prone to human error, costly (antibiotics for 30 days of footbaths runs $2,500 for a 400 cow dairy), subject to governmental restrictions, and do not confer either environmental cleanup or lasting protection from recurrence.

In view of the significant economic damage caused by PDD, an effective way to detect and treat animals infected with the disease, as well as a means to protect them against future infection, is highly desirable.

SUMMARY OF THE INVENTION

The present invention relates to compositions and methods for the detection, prevention and/or treatment of Papillomatous Digital Dermatitis in ruminants.

The present invention now provides a method of preventing and/or treating Papillomatous Digital Dermatitis in ruminants comprising administering to the ruminant a therapeutically effective amount of Serpens spp. bacteria or Serpens spp. bacterin and/or an immunologically active portion thereof and/or an antigenic epitope cross-reactive with Serpens spp.

The present invention further comprises a pharmaceutical composition for preventing and/or treating Papillomatous Digital Dermatitis in ruminants comprising a therapeutically effective amount of Serpens spp. bacteria or Serpens spp. bacterin and/or an immunologically active portion thereof and/or an antigenic epitope cross-reactive with Serpens spp. and a veterinerally acceptable diluent or carrier.

The present invention further comprises a method of determining the presence of PDD antibodies in a sample of ruminant serum comprising contacting the sample with an antigen selected from the group consisting of bacteria or bacterin of the Serpens genus or an immunologically active portion thereof and/or an antigenic epitope cross-reactive with Serpens spp. and detecting antibodies in the sample which bind to the antigen. The present invention can also be used to determine the presence of PDD antigen or anti-Serpens spp. antibodies.

The present invention further comprises the use of a diagnostic kit for determining the presence of PDD antibodies wherein the kit comprises an antigen and one or more binding partners.

The present invention also provides biologically pure Serpens spp. strain HBL-112, and biologically pure Serpens spp. strain HEL-112 bacterin. Serpens spp. strain HBL-112 bacteria Deposit No. 1 and Serpens spp. strain HBL-112 bacterin Deposit No. 2 has been deposited at American Type Culture Collection, 10801 University Boulevard, Manassas, Va. 20110-2209. Serpens spp. strain HBL-112 is a member of the Serpens spp. genus and has the biological and morphological characteristics defined below.

Strain HBL-112 bacteria was deposited with the American Type Culture Collection on Jul. 25, 1997 under the designation "strain HBL-112/1" and was given the accession number ATCC-202,005. Strains HBL-112 bacteria and HBL-112/1 bacteria are identical. In the text and Examples that follow, only the designation "strain HBL-112" will be used to identify the Serpens spp. bacteria of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by the following drawings, in which:

FIG. 1 is a graph showing the clinical reduction in total footwart area seen in dairy cattle with preexisting footwarts in response to vaccination using Serpens spp. strain HBL-112 bacterin, according to the present invention as compared to a control. Wart area is given in square centimeters, calculated from millimeter measurements made in two dimensions of the lesions on the feet of clinically affected cattle. Time is shown as days after enrollment in the trial. Total elapsed time is 76 days;

FIG. 2 is an interaction bar chart of the wart area by initial and postvaccination measurements (at day 49) in vaccinates and controls, with the associated Games-Howell post hoc analysis demonstrating significance of the effect of vaccination;

FIG. 3 is an interaction bar chart and Games-Howell analysis for serological titers in a random sample of about half of the enrolled animals by initial and postvaccination measurements (at day 49) in vaccinates and controls;

FIG. 4a is a graph showing a typical standard curve of a positive bovine serum sample titered in a capture ELISA;

FIG. 4b is a graph showing a standard curve of a competition ELISA using constant antibody and titered antigen;

FIG. 5 is a photomicrograph illustrating the inducible spiral form of Serpens spp., strain HBL-112;

FIG. 6 is a photomicrograph of the same pure culture Serpens spp. strain HBL-112 as FIG. 5 showing the long rods, short rods and spherical bodies typical of the Serpens genus;

FIG. 7 is a photomicrograph of the same pure culture of Serpens spp. strain HBL-112 as FIG. 5 showing flagella associated with Serpens spp. strain HBL-112;

FIG. 8 is a graph show the use of the vaccine of the present invention for prevention of hairy footwarts; and

FIG. 9 shows the serological response of the vaccine of the present invention in naive heifers.

DETAILED DESCRIPTION OF THE INVENTION Isolation and Purification of Serpens spp. Strain HBL-112

Prior to the present invention, the only known species of the genus Serpens was Serpens flexibilis which was isolated from the upper centimeters of sediment (mud) found in eutrophic freshwater ponds. S. flexibilis are rod-shaped cells, 0.3-0.4 μm wide by 8-12 μm long. They occur singly or in pairs. Cells in the stationary phase of growth are longer and often possess blebs or spherical protuberances. S. flexibilis has a uniquely flexible motion. They possess bipolar tufts of 4-10 flagella and also a few lateral flagella. None of the published literature on this organism indicates any proclivity for pathogenesis, nor even any association with animals.

Serpens spp. strain HBL-112 was isolated by the present inventors from wart tissue of cattle suffering from PDD. The wart tissue was minced and filtered into liquid media as well as by direct inoculation into wells cut into soft agar plates. Incubation of parallel cultures was accomplished at 25-37° C. under a variety of atmospheres, such as, 10% CO₂ (candle jar), aerobic, anaerobic and microaerophilic (CampyPak). Final purification of the strain was accomplished by alternate passage between soft agar (0.8%) and standard agar (1.5-2%) plates.

An alternative method for isolating Serpens spp. strain HBL-112 is to mince the wart tissue, place it upon a filter disk (0.45 μm pore size) on a soft agar plate, and incubate it for 2-6 hours under decreased oxygen conditions (candle jar). Removing the filter disk after a short incubation reduces the risk of contamination by swarmers able to swim across the disk but not through it. Using a lowered agar concentration in the agar plate permits rapidly swimming spirochetes (and Serpens spp.) to move through the agar away from lesser mobile bacteria, becoming purified. Repeated sequential passages through the filter/soft agar results in a purified bacterial culture, whether the bacteria is a spirochete or Serpens species, such as Serpens spp., strain HBL-112.

The rate of movement through the soft agar can be used to distinguish between spirochetes and Serpens spp. In very soft agar (0.5%) Serpens flexibilis moves 4 mm/hour, reaching the edge (from the center) of a 100 mm agar plate in approximately 12 hours while very fast spirochetes move only 0.5 to 0.8 mm/hour. In soft agar (0.8%), S. flexibilis moves 2 mm/hour, while Serpens spp. strain HBL-112 moves approximately 1.5 mm/hour.

Microscopic Morpholooy and Motility

Light microscopy of Serpens spp. strain HBL-112 reveals a poorly staining gram negative rod, often curved, with typically 0.5% to 5% of the cells (up to 100% depending upon media constituents and growth conditions) demonstrating rigid spirals (FIG. 5). As shown in FIG. 6, the Serpens spp., strain HBL-112 bacteria are highly pleomorphic, with three main forms seen: straight or curved rods, "polliwogs" or spherical cyst-like structures, and rigid spirals. Rods may or may not have sections of rigid spirals interspersed with straight sections. Variations in growing conditions will induce a greater preponderance of one or another form seen under "standard " conditions.

Wet mount phase contrast microscopy of Serpens spp., strain HBL-112 curved and straight rods on the cut edge of a soft agar block reveals the unique and characteristic flexing and serpentine motility reported for Serpens flexibilis. The rods, but not the polliwog or rigid spiral forms, demonstrate a swimming to serpentine motion, with the serpentine motion and flexibility especially evident under higher viscosity conditions. Direction reversal is rapid, with organisms capable of movement in either direction along their longitudinal axis. Rigid spirals often appear non-motile. "Polliwog " and cyst forms display a swimming/wriggling motility similar to true polliwogs. Using wet mount slides taken from standard agar plates, the morphology of young cultures is predominantly rods. Older cultures exhibit vastly differing rod forms, as well as coccoid and polliwog forms.

With the "soft " agar medium, Serpens spp. are observed by cutting a small agar block out and dicing it onto the slide. Serpens spp. which are observed within the agar or in contact with it exhibit the serpentine motility. Serpens spp. which are washed away from the agar are generally in the rod form, although they exhibit flexing and a spiral-like motility.

A rigid spiral form of Serpens spp. strain HBL-112, as shown in FIG. 5, occurs rarely in many media, but becomes more frequent in media containing higher concentrations of sulfur compounds such as cysteine and thioglycollate. When these compounds are added in even higher concentrations, the organism can be converted to nearly 100% spiral form.

Transmission electron microscopy confirms the three predominant morphological phenotypes. Axial filaments (flagella lying adjacent to the bacterial cell, within a cell membrane) characteristic and essential for identifying an organism as a spirochete, are not present in Serpens flexibilis nor in Serpens spp., strain HBL-112. Flagella are seen attached terminally on some of the straight and curved rods, and also along the sides of the organism (lateral flagella); the number of flagella on each end (terminal or subterminal) is expected to be approximately 2-4 as shown in FIG. 7.

Biochemistry

Biologically pure Serpens spa., strain HBL-112 of the present invention and Serpens flexibilis were characterized by the standard biochemical reactions reported in Tables 1a and 1b below. Table la presents data on the biochemical reactions of Serpens flexibilis, Serpens spp., strain HBL-112, of the present invention, as well as three bacterial genera thought to be closely related to the Serpens genus, which currently remain unassigned to a bacterial Family according to Bergey's Manual of Determinative Bacteriology.

Table 1b presents data on the enzyme reactions of Serpens flexibilis, Serpens spp., strain HBL-112, two spirochete strains proposed by CVDLS (California Veterinary Diagnostic Laboratory System) as possible etiological agents for PDD, and a broad sampling of spirochete genera related to the two CVDLS spirochete strains. The "CVDLS isolate " is actually seven strains of spirochete isolated in conjunction with hairy footwart lesions, all having the same enzyme reactions. CVDLS 1-9185 MED is an eighth strain of spirochete which has a different enzyme profile than the other CVDLS isolates.

                  TABLE 1a                                                         ______________________________________                                         Summary of Biochemical Reactions                                                         HBL #112 ATCC      Pseudo-                                                                              Alcali-                                     Biochemical                                                                              Serpens  29606     monas genes Vibrio                                Reaction  spp.     S. flexibilis                                                                            spp.  spp.  hollisae                              ______________________________________                                         ONPG      -        -         -     -     -                                     Arginine  -        -         -     -     -                                     dihydrolase                                                                    Lysine    -        -         -     -     -                                     Decarboxylase                                                                  Ornithine -        -         -     -     -                                     Decarboxylase                                                                  Citrate as                                                                               -        -         -     -     -                                     sole C-source                                                                  H2S Production                                                                           -        -         -     -     -                                     Urea hydrolysis                                                                          -        -         -     -     -                                     Tryptophan                                                                               -        -         -     -     -                                     deaminase                                                                      Indole Production                                                                        -        -         -     -     +                                     VP        -        +         -     -     -                                     Hydrolyzes                                                                               -        -         +     -     -                                     Gelatin                                                                        Ferments:                                                                      Glucose   -        -         -     -     -                                     Mannose   -        -         -     -     -                                     Inositol  -        -         -     -     -                                     Sorbitol  -        -         -     -     -                                     Rhamnose  -        -         -     -     -                                     Saccharose                                                                               -        -         -     -     -                                     Melibiose -        -         -     -     -                                     Amygdalin -        -         -     -     -                                     Arabinose -        -         -     -     +                                     Oxidase   +        +         +     +     +                                     Reduces nitrate                                                                          +        +         +     +     +                                     to nitrite                                                                     Reduces nitrite                                                                          -        +         -     -     -                                     to nitrogen                                                                    Motility  +        +         +     +     +                                     Catalase  +        +         N*    N     N                                     ______________________________________                                          *N = not available                                                       

                                      TABLE 1b                                     __________________________________________________________________________     Comparison of Enzyme Reactions                                                           Related Bacterial Spp.                                                                                                  Human Human                           HBL Isolate,                                                                         ATCC      CVDLS    Leptospira                                                                           Triponema intestinal                                                                           & avian                         Strain #112                                                                          Strain                                                                              CVDLS                                                                               1-9185                                                                              Borrelia                                                                           iriterrogans                                                                         spp. Serpulina                                                                           spirochetes                                                                          spirochetes           Enzyme Composition                                                                       (1)*  29606 (1)                                                                           Isolate (7)                                                                         MED (1)                                                                             spp. (6)                                                                           (12 ) (oral) (1)                                                                          spp. (8)                                                                            (2)   (4)                   __________________________________________________________________________     Alkaline phosphatase                                                                     .5    .5   +    +    .5-2                                                                               2-4   2    3-5  1     1-2                   Esterase (C4)                                                                            2     2    +    +      0-0.5                                                                            .5    .5   1-4  1     0-2                   Esterase lipase (C8)                                                                     4     4    +    +    1   2-3   .5-1 1-4  1     2                     Lipase (C14)                                                                             1     .5   -    -    -   1-2   -    -    -     -                     Leucine arylamidase                                                                      3     4    -    -    2-4 3     -    -    -     -                     Valine arylamidase                                                                       .5    .5   -    -    -   .5-1  -    -    -     -                     Cystine arylamidase                                                                      -     -    -    -    -   .5-1  -    -    -     -                     Trypsin   -     -    -    +    -   -     -    0-2  -     -                     Chymotrypsin                                                                             -     -    -    +    -   -     -    0-5  -     -                     Acid phosphatase                                                                         .5    .5   +    +    1-2 3     3-4  3-5  1     2-4                   Naphthol-AS-BI-                                                                          .5    1    +    +    .5-1                                                                               .5-2  .5   0-2  -      0-.5                 phosphohydrolase                                                               α-galactosidase                                                                     -    -    -    -    -   .5-2  -    3-5  -     .5-3                  galactosidase                                                                            -     -    +    -    -   1     5    5    1     4                     β-glucuronidase                                                                     -     -    +    -    -   -     5    3-4  -     -                     α-glucosidase                                                                      -     -    -    -    -   1     -    2-5  -     .5                    glucosidase                                                                              -     -    -    -    -   1     -    3-5  -     .5                    N-acetyl-β-                                                                         -     -    +    -    -   -     4    -    -     l5                    glucosaminidase                                                                α-mannosidase                                                                      -     -    -    -    -   -     -    -    -     -                     α-fucosidase                                                                       -     -    -    -    -   -     1    -    -     -                     __________________________________________________________________________      *(#) = # isolates or strains tested                                            - = no detectable enzyme reaction                                              .5 = <5 nonomoles enzyme                                                       1 = 5 nonomoles enzyme                                                         2 = 10 nanomoles enzyme                                                        3 = 20 nanomoles enzyme                                                        4 = 30 nanomoles enzyme                                                        5 = 40+ nanomoles enzyme                                                       + = positive, but no level given                                         

As shown in Table 1a, Serpens spp. strain HBL-112 of the invention is very weakly catalase positive by peroxide, oxidase positive by spot oxidase testing (Difco Spot-test), and gives the following reactions after forty-eight hours of incubation (at 35-36° C.) on API 20E strips (bioMerieux): negative for ONPG (o-nitrophenyl-β-D-Galactopyranoside), negative for arginine dihydrolase, negative for lysine decarboxylase, negative for ornithine decarboxylase, does not use citrate, does not produce hydrogen sulfide from thiosulfate, negative for urease, negative for tryptophan deaminase, does not form indole from tryptophan, does not produce acetoin from pyruvate, does not liquify gelatin, and does not ferment any of the 20E sugars (glucose, mannitol, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin, L+arabinose); it does reduce nitrate to nitrite, but not to nitrogen gas.

As illustrated in Table 1a, Serpens sp., strain HBL-112 is distinct from S. flexibilis in that it gives a negative Voges-Proskauer reaction (VP) whereas the S. flexibilis gives a positive reaction. The Voges-Proskauer test is used to determine the bacteria's ability to metabolize pyruvate into acetoin, an intermediary glucose metabolite. Another clear difference is the ability of the Serpens spp., strain HBL-112 to migrate through soft (0.8%) agar plates. S. flexibilis migrates about 2 mm/hour whereas Serpens spp., strain HBL-112 migrates about 70-80% as fast. S. flexibilis' faster velocity through soft agar is matched by its higher growth rate in several medias including both Mueller Hinton broth and TSBA plates.

As shown in Table 1b, Serpens spp., strain HBL-112 gives the following reactions after a four hour incubation at 35-36° C. for the enzymes on the API-ZYM (bioMerieux) test strip after forty-eight hours aerobic growth on tryptic soy agar blood plates or in OTI broth or Mueller Hinton broth: weakly positive for alkaline phosphatase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, and valine arylamidase; positive for C4 esterase and C14 lipase; strongly positive for C8 esterase-lipase and leucine arylamidase. The remaining eleven enzymes tested for on this strip were negative. Under the same growth conditions, Serpens flexibilis yields identical results.

Growth Parameters

Serpens spp., strain HBL-112, is capable of growth on solid phase standard tryptic soy blood agar (TSBA), Mueller Hinton, and chocolate agars (1.5-2% agar) or soft BSK-H (0.8% agar) plates under aerobic, anaerobic, 10% CO₂ (candle jar), and microaerophilic (BBL Campypak or Campypak Plus) conditions. With more oxygen, the organism has a slightly increased ability to migrate across the top of the agar surface. Growth on TSBA and BSK-H agar in these atmospheres occurs at 25° C., 30° C., and 35-36° C.; the temperature range is not however fully defined yet.

Serpens spp., strain HBL-112 is capable of growth suspended in liquid media in modified Eagle's media (MEM), Mueller Hinton broth, and fluid thioglycollate (FTG) media at 35-36° C. The addition of sterile donor horse serum at 2-5% (v/v) does not appear to affect growth in these medias.

Serpens spp., strain HBL-112 is capable of growth in standard microbiological liquid media at a pH range of 6.8 to 9.4, with optimum growth at approximately pH 7.4.

As used herein, the term, "Serpens spp. strain HBL-112" means bacteria of the Serpens spp. strain HBL-112 having the biochemical reactions set forth in Tables 1a and 1b.

The present invention encompasses the use of Serpens spp. strain HBL-112, Serpens flexibilis, or other Serpens species bacteria, and/or an immunologically active portion thereof, and/or an antigenic epitope substantially cross-reactive with immunologically active portion(s) of Serpens species bacteria to provoke a protective immune response against PDD in ruminant species for the prevention and/or treatment of PDD.

A vaccine containing the bacteria or bacterin may be administered to animals having symptoms of PDD, or administered to animals having no signs of the disease.

The present invention provides methods and compositions for the prevention and/or treatment of PDD in ruminants, such as bovine, ovine and caprine species, comprising an effective amount of Serpens bacteria (live or killed) or an immunologically active portion thereof and an immunologically rational carrier, adjuvant, emulsifier and/or diluent herefor. Suitable Serpens bacteria are Serpens spp. strain HBL-112 and S. flexibilis bacteria, preferably Serpens spp. strain HBL-112. The killed bacteria may be conveniently prepared by propagation of pure culture Serpens spp. in conventional microbiological media, killing the bacteria by any suitable known method, and standardizing the antigenic mass to an appropriate CFU/ml equivalent. Where live vaccines are desired, the killing step is omitted, but the rest of the formulation proceeds as for the killed suspension. Where the purpose is to prepare a vaccine, suitable carrier(s), adjuvant(s), emulsifier(s), and/or diluent(s) may then be added to the (live or killed) bacterial suspension.

The composition of the present invention for the prevention and/or treatment of PDD may be prepared in a conventional manner by admixing the Serpens spp. killed or live bacterial suspension or an immunologically active portion thereof with an immunologically rational carrier, adjuvant, emulsifier and/or diluent, such as aluminum hydroxide or pharmaceutical grade mineral oil and emulsifier.

It is presently preferred to administer the composition of the present invention by subcutaneous administration, although parenteral or oral administration may be used as well. Oral compositions may incorporate the Serpens spp. bacteria or an immunologically active portion thereof or an antigenic epitope substantially cross-reactive with immunologically active portion(s) of Serpens spp. bacteria in drinking water or feed.

Although the dosage and regimen must in each case be adjusted, using professional judgment and considering the weight of the animal, generally the dosage will be from about 1×10⁸ to about 1×10¹¹ CFU/ml, preferably from about 1×10⁹ to about 1×10¹⁰ CFU/ml based upon a 5 ml dose administered subcutaneously. In some instances, a sufficient therapeutic dose can be obtained at a lower dose while in others a larger dose will be required.

Although FIG. 1 shows vaccine doses administered at day 0, day 8 and day 35, it is presently preferred to administer two to three doses, the first at day zero, the second dose three to four weeks later and when desirable a third dose may be administered about three to four weeks after the second dose. Suitably, the doses will contain the same amount of bacteria or bacterin.

Parenteral administration can be effected utilizing liquid dosage unit forms such as sterile solutions and suspensions intended for subcutaneous, or intramuscular injection. These are prepared by suspending or dissolving a measured amount of the prepared bacterial suspension in a non-toxic sterile liquid vehicle suitable for injection, such as a sterile aqueous or oleaginous medium. Alternatively, a measured amount of the sterile bacterial suspension is placed in a sterile vial and sealed, or lyophilized and sealed. An accompanying sterile vial or vehicle can be provided for mixing prior to administration. Nontoxic salts and salt solutions can be added to render the injection isotonic. Adjuvants, stabilizers, preservatives and emulsifiers can also be added.

The present invention provides a method for the diagnosis of PDD and the detection of Serpens antibodies or Serpens antigens using conventional immunoassay methods. Sera from clinically affected or exposed but unvaccinated animals reacts with the Serpens antigen if it contains antibodies to the bacteria. Bound antibodies may be measured. Therefore the Serpens antigen can be used in a diagnostic test for screening of unvaccinated animals for prior exposure to the agent. Similarly, such a diagnostic test may also be used to assess the immune status of a vaccinated animal with respect to the Serpens antigen.

Conversely, antibodies made in and harvested from animals vaccinated with the Serpens bacteria may be utilized for the detection of Serpens bacteria.

A method for determining the presence of PDD antigen in a sample of ruminant tissue comprises administering a Serpens spp. bacteria or Serpens spp. bacterin and/or an immunologically active portion thereof and/or an antigenic epitope cross-reactive with Serpens spp. to the ruminant, harvesting the resultant antibodies or harvesting antibody producing cells and subsequently harvesting antibodies from those cells, binding the antibodies to binding partners and directly or indirectly measuring the binding reaction.

Serpens antigens, or anti-Serpens antibodies, or immunologically active fractions of either, may be used in a process designed for the concentration or purification of the corollary binding partner for use as a reagent.

A method for determining the presence of PDD antibodies in a sample of ruminant serum may suitably comprise contacting the sample with the Serpens spp. bacteria, preferably Serpens spp. strain HBL-112 bacteria, and detecting antibodies in said sample which bind to said antigen. A method for detecting PDD, or exposure to the Serpens bacteria thereof, via determining the presence of Serpens antibodies in a sample of ruminant serum may suitably comprise incubation of the sample with a solution containing at least one binding partner capable of binding to Serpens antibodies, and directly or indirectly determining the presence of conjugated binding partners in the sample.

The present invention uses serum for the samples and Serpens antigen as the respective binding partner, however the specific binding reaction may be utilized to detect either partner, hence other samples such as tissue sections, cell smears and parts thereof, or environmental samples, Serpens per se or fractions thereof may be studied using this method.

Either binding partner may incorporate one or more detectable markers such as a radioisotope, metal or fluorochrome, or may be detected indirectly, as through the use of conjugated enzyme with substrate detection.

Alternatively, in cases where neither of the primary binding partners incorporates a marker or other means for direct detection, secondary binding partnerships may be formed for subsequent detection either using Serpens group antigens or their complementary antibodies and/or anti-Serpens antibodies or through the use of binding partners which are not Serpens related, (such as avidin-biotin) but which may be used directly or indirectly for the detection of the primary binding partners.

Subsequent detection and quantification of the above markers, binding partnerships or other measurable medium may be by any conventional means appropriate to the methodology.

Alternatively, detection of Serpens in a sample can be made by means of directly or indirectly measuring physical features distinct to or characteristic of Serpens. Such measurements can include detection and measurements of compounds, or compound mixtures, including lipids, proteins or nucleic acids such as used in DNA amplification and identification techniques, or chromatographic separation and identification techniques such as gas or liquid chromatography.

In a further aspect of the invention, there is provided a diagnostic kit for use in performing the method according to the invention, which kit comprises Serpens antigen and one or more binding partners. The diagnostic kit may further include reagents required for sample preparation and optionally reagents for the detection of the bound antibody.

The present invention is illustrated in terms of its preferred embodiments in the following examples. All temperatures are in degrees Centigrade and all parts and proportions are by weight, unless otherwise noted.

EXAMPLE 1

Whole-cell Serpens spp. strain HBL-112, Serpens flexibilis or other Serpens sep. bacterins (killed cultures) are prepared by propagating bacterial cells in a standard microbiological media, killing the cells with formaldehyde, washing with sterile saline to remove cell debris, unused media components, bacterial waste products and the like, and suspending the bacterin in sterile phosphate buffered saline with 10% (v/v) aluminum hydroxide (adjuvant) and 0.01% thimerosal (preservative).

EXAMPLE 2

Whole-cell Serpens spp. strain HBL-112 or Serpens flexibilis or other Serpens spp. bacterins (killed cultures) are prepared by propagating bacterial cells in a standard microbiological media, killing the cells with formaldehyde, washing with sterile saline to remove cell debris, unused media components, bacterial waste products and the like, and emulsifying the bacterin in sterile phosphate buffered saline with 25% (v/v) pharmaceutical grade mineral oil and emulsifiers (adjuvant) and 0.01% thimerosal (preservative).

EXAMPLE 3

A non-virulent Serpens spp. or other apathogenic bacterial strain bearing cross-protective Serpens like antigens is propagated under standardized conditions (for example: using one of several conventional microbiological medias with a pH between 6.8 to 9.4, incubated at a temperature of approximately 25-37° C. under one of a variety of atmospheres for a period of a few days to several weeks) ascertained to be a pure culture by suitable testing such as microscopic and colonial morphology, velocity through soft agar, characteristic motility under phase contrast microscopy, and/or biochemical testing and is then harvested. The harvested cells are washed, suspended in a sterile vehicle (for example, buffered saline) containing any conventional cryoprotectant typically used in vaccine manufacturing, filled into sterile vials and preserved by either freezing or lyophilization. The preserved material is thawed or reconstituted for administration either subcutaneously, orally or parenterally to ruminants at the appropriate dosage.

EXAMPLE 4

A total of 76 dairy cows with active, untreated lesions of PDD were enrolled in a treatment-based vaccine trial. Fifty animals were from the first milking string (highest producing cows), and twenty-six were from the hospital string. Since the hospital cows were likely undergoing treatment for mastitis which may have altered their immunological profile, only the first string cows were sampled and followed serologically.

All animals were scored for lameness and number of feet involved at the start of the trial; within lameness/foot groupings, each cow was randomly assigned to receive either vaccine or placebo for the trial. On the first day and approximately twice weekly thereafter each animal's feet were cleaned with plain water sprayed under moderate pressure from a hose-end sprayer and evaluated for presence, painfulness, number and size of PDD lesions; on each visit, milk production was recorded for evaluation as a possible covariate, and information on gestational status, age, lactation number and days in milk were obtained to evaluate possible covariates or confounders. Scoring was performed in a "blinded " fashion: the barn sheets did not show which animals were vaccinates and which were controls, and the number of enrolled animals precluded memorization of their status.

A 5.0 ml dose of vaccine or placebo was administered to each animal. The vaccine contained 2×10⁹ CFU per ml of Serpens spp. strain HBL-112 bacterin suspended in sterile phosphate buffered saline with 10% (v/v) aluminum hydroxide and 0.01% thimerosal. The placebo contained no bacterin, bacteria or bacterial antigens, but was otherwise identical to the vaccine. The vaccine or placebo was administered to each enrolled animal on day 0, day 8, and day 35; initially, a two-dose closely spaced sequence was sought to determine whether or not the vaccine could be used therapeutically. Over the course of three to four weeks, clinical improvements were seen in many of the trial animals as shown in FIG. 1. Clinically, there seemed to be a "plateau " in continued improvement, so the decision was made to administer a "booster " dose of vaccine at the fifth week in the trial. Part of the plateau was subsequently found due to the presence of persistent scar tissue which was being erroneously scored as wart tissue.

The reason the control group begins to show improvement after day 40 (FIG. 1), was that an oxytetracycline footbath was administered to the vaccinate and control cows. However, the vaccinates maintained their statistically significant advantage over controls in wart area reduction despite the improvement in controls attributable solely to the oxytetracycline footbath.

Three animals showing signs of lameness did not have evidence of lesions upon enrollment. When they did not develop lesions by eight weeks into the trial, they were dropped from the lesion analysis portions of the trial. Two of these animals did provide some useful information: neither was serologically positive on ELISA testing using Serpens spp. strain HBL-112 as the antigen, suggesting no prior exposure to the epitopes on this organism. That these non-lesion bearing animals did not recognize the Serpens spp. strain HBL-112 in an ELISA, while lesion-bearing nonvaccinates (controls) did, strongly suggests that a Serpens spp. bacteria is involved in the pathogenesis of the PDD lesion.

FIGS. 2 and 3 show effects occurring prior to any effect from the antibiotic footbath; the clinical effects seen in vaccinates (and lack thereof in controls) are thus attributable solely to the use of Serpens spp. strain HBL-112 bacterin. Further, limiting the data in the bar charts to results seen only through day 49 underreports the clinical improvement seen following the third dose of vaccine administered on day 36.

A total of forty-five animals were bled three times during the trial for measuring antibodies to PDD. Twenty-two serologically monitored cows were vaccinates, including two non-wartbearing animals; twenty-three animals were controls. As shown in FIG. 3, all wart-bearing animals (both vaccinates and controls) were seropositive to Serpens spp. strain HBL-112 on initial (prevaccination) ELISA testing, indicating prior or concurrent exposure to the same or cross-reacting epitopes of HBL's vaccine strain. FIG. 3 further illustrates that while the control animals decreased in ELISA titer over the course of the trial, vaccinates showed titer increases, indicating that the vaccine was prompting an immunological response. Since this titer rise was detectable as early as eight days after the first (and at that time only) vaccination, it strongly suggests that the vaccine was prompting an anamnestic response in vaccinates, not simply a primary response (which typically requires 14-21 days to become detectable).

Generally, the absolute titer value was higher (albeit not significantly: 0.460 versus 0.441) among controls compared with vaccinates at the start of the trial, and remained the same or decreased over the course of the trial for twenty of twenty-three controls. The three controls showing small titer increases were also among those with the largest total lesion area during the trial; exposure to the agent in the lesions would account for the slight rise. Twenty-one of the twenty-two vaccinates showed a fairly large increase in titer (0.441 increased to 0.560) in response to vaccination; one animal showed a small decrease in titer.

Table 2 below, presents Type III Sums of Squares tables for dependent variables wart area and titer, showing statistically significant differences between vaccinates and controls in response to vaccination. While the herd as a whole improved significantly in lesion size (wart area) between the start of the trial and after 49 days (p value=0.0420), the most significant effect is attributed to the vaccinates: p value=0.0155 for the interaction of pre-post with vaccination status (=group). The change in titer seen in the herd as a whole between the start of the trial and at 49 days is solely attributable to the increases seen in vaccinates (p value for pre-post by group is highly significant at p value=0.0001 vs pre-post effects alone at p value=0.2682).

Table 3 below, presents a series of pre- and post-vaccination Means tables for the dependent variables examined in the analysis of the vaccine trial.

Of the factors measured, only total wart area shows statistically significant (@p<0.05) differences between vaccinates and controls. Vaccinates definitely did not develop as large lesions, nor did they remain lesioned as long as controls. See FIGS. 1-3.

                  TABLE 2                                                          ______________________________________                                         Type III Sums of Squares                                                                        Sum of    Mean                                                Source     df    Squares   Square F-Value                                                                               P-Value                               ______________________________________                                         Dependent: Lesion Area                                                         Group      1     185.306   185.306                                                                               2.005  .1643                                 Milk Production                                                                           1     5.012     5.012  .054   .8170                                 Milk Pro . . .                                                                 Subject (Group)                                                                           41    3789.260  92.421                                              pre/post   1     114.663   114.663                                                                               4.474  .0420                                 pre/post * Group                                                                          1     166.998   166.998                                                                               6.516  .0155                                 pre/post * Milk                                                                           1     102.986   102.986                                                                               4.018  .0533                                 Product . . .                                                                  pre/post * Subject                                                                        33    845.727   25.628                                              (Gro . . .                                                                     Dependent: Titer                                                               Group      1     .057      .057   1.774  .1902                                 Milk Production                                                                           1     .001      .001   .037   .8492                                 Milk Produ . . .                                                               Subject (Group)                                                                           41    1.310     .032                                                pre/post   1     .004      .004   1.268  .2682                                 pre/post * Group                                                                          1     .099      .099   35.402 .0001                                 pre/post * Milk                                                                           1     8.995E-5  8.995E-5                                                                              .032   .8584                                 Productio . . .                                                                pre/post * Subject                                                                        33    .092      .003                                                (Group)                                                                        ______________________________________                                    

                  TABLE 3                                                          ______________________________________                                         Means Table                                                                    Effect: pre/post * Group                                                                Count Mean      Std. Dev.                                                                               Std. Error                                   ______________________________________                                         Dependent: Lesion Area                                                         pre, vaccinate                                                                            20      10.850    7.252  1.622                                      pre, control                                                                              23      11.504    6.614  1.379                                      post, vaccinate                                                                           15      8.220     9.115  2.353                                      post, control                                                                             22      15.345    9.005  1.920                                      Dependent: Lesion #                                                            pre, vaccinate                                                                            20      1.850     .988   .221                                       pre, control                                                                              23      2.087     1.276  .266                                       post, vaccinate                                                                           15      2.333     1.397  .361                                       post, control                                                                             22      3.000     1.574  .335                                       Dependent: Feet Affected                                                       pre, vaccinate                                                                            20      1.750     .967   .216                                       pre, control                                                                              23      1.783     .736   .153                                       post, vaccinate                                                                           15      2.067     1.100  .284                                       post, control                                                                             22      2.227     .813   .173                                       Dependent: Lameness                                                            pre, vaccinate                                                                            20      1.400     .883   .197                                       pre, control                                                                              23      1.261     .810   .169                                       post, vaccinate                                                                           15      .533      .516   .133                                       post, control                                                                             22      .818      .733   .156                                       Dependent: Titer                                                               pre, vaccinate                                                                            20      .441      .134   .030                                       pre, control                                                                              23      .460      .123   .026                                       post, vaccinate                                                                           15      .560      .173   .045                                       post, control                                                                             22      .444      .130   .028                                       ______________________________________                                    

EXAMPLE 5

The same antigen present in the vaccine, Serpens spp. strain HBL-112 bacterin, is also used in an ELISA test to monitor serological response to vaccination. Antigen (a 5% suspension of concentrated killed, washed whole cells, Serpens spp. strain HBL-112 bacteria, approximately 5×10⁸ cells/ml, in a coating buffer, a sodium carbonate/bicarbonate buffer at pH 9.6) is placed in the wells of a 96-well microtiter plate overnight at room temperature. The plate is gently washed using a wash buffer, (a sodium phosphate buffer containing a detergent such as Tween or Triton (pH 7.5)). A bovine serum sample (primary antibody) is added and incubated in the plate at room temperature for one hour. The plate is gently washed again using wash buffer to get rid of unbound antibodies. A secondary antibody made of an anti-cow antibody, such as from goat, conjugated with alkaline phosphatase is incubated in the plate for one hour at room temperature. The plate is gently washed again using wash buffer. The plate is then incubated with p-nitrophenyl phosphate substrate in a 10% diethanolamine buffer (pH 9.8) and allowed to develop at room temperature until the maximum well O.D. is approximately 0.8 to 1.0, no stopping agents are used. The alkaline phosphatase enzyme attached to the secondary antibody converts the p-nitrophenyl phosphate substrate and turns the clear solution in the plate yellow. Binding of the primary antibody, secondary antibody and hence the strength of the O.D. reading is proportional to the amount of antibody present in the cow serum against the Serpens spp. strain HBL-112 antigen.

This method is essentially standard for ELISA, and any other ELISA method and numerous variations in this procedure would be expected to produce similar results. The procedure does differ from typical ELISA methods in that the incubation steps are done at room temperature. The purpose of this is only to reduce intrawell variation due to temperature induced edge effects.

Sera from unvaccinated animals binds to the Serpens spp. strain HBL-112 bacteria antigen if it contains antibodies for the bacteria.

EXAMPLE 6

It is often desirable to use a multivalent (multiple antigen) vaccine preparation to minimize the number of times an animal must be injected. Using a single pharmaceutical preparation which incorporates multiple antigens minimizes pain and risk of infection (abscesses at the injection site) for the animal, and decreases labor costs and risk of human injury (handling injuries and/or accidental self-injection) for the owner and their employees.

The same antigen used alone to produce the vaccines described in Examples 1 and 2 may also be used in combination with either antigens to produce a multivalent vaccine useful for treating and/or preventing other bacterial infections of ruminants in addition to PDD. The flexibility of the Serpens spp. vaccine schedule would permit virtually any other currently used ruminant vaccine antigen to be advantageously incorporated with Serpens spp. in a vaccine for simultaneous administration. Alternatively, the Serpens spp. antigen could be incorporated into any other ruminant pharmaceutical preparation administered by any method other than the intravenous route.

For example, strains of anaerobic bacteria such as members of the Bacteroides and/or Fusobacterium genera which are causative agents of the condition known as footrot in cattle and sheep may be incorporated with Serpens spp. antigens in a pharmaceutical preparation which when administered to susceptible ruminants will prevent both PDD and footrot. In another example, prevention of PDD in dairy cows may optimally require vaccination with Serpens spp. antigens during the non-milking "dry " period since the outbreaks of disease appear to peak during the first few months after lactation starts. Since many other vaccines are administered to the cow during this period to provoke high maternal antibody titers for transmission to the calf via colostrum, the Serpens spp. antigen may be advantageously administered to the cow with these other vaccine antigens during this dry period.

Alternatively, certain other antigens are known to have general immune-stimulatory properties, such as the "superantigen " present in members of the Staphylococcus genus or the "core antigen " of certain members of the coliform bacteria such as the J-5 strain of Escherichia coli, when incorporated into vaccines with the primary antigen. In this case, incorporation of any suitable immune-stimulatory antigen with Serpens spp., strain HBL-112 or related antigen(s), results in a vaccine with enhanced immunoprophylactic properties.

EXAMPLE 7

The study utilized a double-blind, randomized block, prospective cohort design. Cows with existing PDD lesions were divided into two equal groups on the basis of lameness score and number of feet affected. One group was randomly chosen to be vaccinated with three 5.0 ml doses of a vaccine containing 3.3×10⁸ CFU per ml of Serpens spp. strain HBL-112 bacterin suspended in sterile phosphate buffered saline with 10% (V/V) aluminum hydroxide and 0.01% thirmerosal, and the other group was given 5.0 ml doses of a placebo identical to the vaccine but containing no bacterin.

For each measurement, the cows' feet were cleaned with water and the two-dimensional area of the warts was measured with a millimeter ruler by persons unaware of each cow's vaccination status. Reevaluation of warts was performed six and one half months after initiating the study. Literature reports indicate an expected recurrence rate in excess of 60% seven to twelve weeks after bandaging lesions.

Table 4 below report the results of the use of the three doses of the vaccine as compared to the control. When the total wartarea is averaged over just wart-bearing animals rather than the whole group, it can be seen in Table 4 below that all thirty-four vaccinates improved in terms of decreasing lesion size, whereas only the thirteen controls which healed showed decreases in average wart area in response to the oxytetracycline and lincocin footbaths. All vaccinates responded to the combination therapy (vaccine with footbath) whereas two-thirds of the controls did not improve with the footbath alone.

    ______________________________________                                         Decreased Prevalence of Hairy Footwarts Following                              Vaccination with Serpens species Bacterin                                                 VACCINATES  CONTROLS                                                                     #    prev- avg  #    prev- avg                            Date  Time    lesion cows alence                                                                               Wa   cows alence                                                                               Wa                             ______________________________________                                         Apr-96                                                                                0 wks  warts  34   100.0%                                                                               10.3 37   100.0%                                                                               10.2                                         total  34              37                                        Jun-96                                                                               10 wks  warts  11    32.4%                                                                               4.6  23    63.9%                                                                               11.7                           5 wks post vacc.                                                                         no     22      64.7%     13    36.1%                                           warts                                                                          not     1      2.9%       0    0.0%                                            seen*                                                                          total  34                36                                          Sep-96                                                                               24 wks  warts   9    26.5%                                                                               6.5  16    44.4%                                                                               5.8                            19 wks post vacc.                                                                        no     19      55.9%     13    36.1%                                           warts                                                                          not     5     14.7%       1    2.8%                                            seen*                                                                          sold    1      2.9%       6    16.7%                                           total  34                36                                          ______________________________________                                          *dry cows                                                                

On average, all vaccinates improved over the course of the trial; only one third of the controls improved in terms of decreasing lesion size. Of the eleven vaccinated animals with warts at the end of the ten week trial, five had progressed to complete resolution by six months. At the six month check, three vaccinates had developed new lesions indicating a recurrence rate of only 10.7% (3/28). The controls at six months had insufficient healed animals to measure a recurrence rate. By six months, wart prevalence among controls had decreased to 44.4% (16/37) using lincocin footbaths, however, the apparent improvement does not take into account that five animals were culled for intractable footwarts.

EXAMPLE 8

A total of 88 Holstein cows and heifers were divided into three equal groups based on age, parity, DIM, production and SCC from the most recent DHIA test data. Each group was assigned its vaccination status (F1=29 animals; F2=29 animals; control=30 animals) randomly. The animals in groups F1 and F2 were vaccinated at monthly intervals with 5.0 ml of a vaccine containing 7.9×10⁸ CFU per ml of Serpens ssp. strain HBL-112 bacterin suspended in sterile phosphate buffered saline with 10% (V/V) aluminum hydroxide and 0.01% thimerosal for a total of three doses of vaccine. The control used 5.0 ml doses of the placebo used in Example 7. Prevalence of warts in each group was determined by visual inspection at the start of the trial, and the incidence of new cases was determined by visual inspection at weekly intervals.

As shown in FIG. 8, both of vaccinated groups F1 and F2 exhibited protected effects against wart development over a period of fourteen weeks compared to controls. (Group F1 had an incidence of 3 new wart cases (3/24 at risk=12.5%) while group F2 had an incidence of 2 new wart cases (2/23 at risk=8.7%). Over the same time period, the control incidence was 11 new wart cases (11/26 at risk=42.3%), meaning that controls were nearly four time more likely to develop warts than were vaccinates over the fourteen weeks. This trial is continuing and as FIG. 8 shows, there is no sign yet that new wart cases in the controls will cease, while the vaccinates have not had any new cases develop since receiving the third dose of the vaccine. FIG. 8 thus shows the effectiveness of the Serpens SpP bacterin vaccine in preventing development of new wart cases in a whole-herd vaccine trial.

EXAMPLE 9

A total of 88 Holstein cows and heifers were divided into three equivalent groups based on age, parity, DIM, production and SCC from the most recent DHIA test data. The assignment of vaccination status to each group was accomplished randomly. There were a total of four heifers in the controls, five in the F1 of vaccine group, and six in the F2 vaccine group. Animals were vaccinated at monthly intervals with 5.0 ml doses the vaccine used in Example 8 for a total of three doses of vaccine. the controls were administered 5.0 ml doses of the placebo of Example 8. Whole cell antigen ELISA titers were determined on all four serum samples from each animal at one time to minimize interplate, operator, and reagent variability. Titers were determined din comparison with an established standard curve for this antigen.

FIG. 9 shows the serological response to the vaccination in non-wart bearing first calf heifers evaluated one month following each of three doses of bacterin, and compared to baseline levels and control animals. The major titer rise in vaccinates occurred subsequent to the second dose of bacterin; a third dose does not appear to add much of a titer increase.

Baseline values for all three groups were indistinguishable. Control animals' titers remained at baseline values for the duration of the study. Both vaccinate groups experienced an average three-fold titer rise in response to the first dose of bacterin, with a subsequent three to six fold increase following the second dose. A third dose of bacterin resulted in negligible titer increases. 

What is claimed is:
 1. Biologically pure Serpens spp. strain HBL-112 (ATCC 202005).
 2. A pharmaceutical composition for the prevention and treatment of Papillomatous Digital Dermatitis in ruminants comprising a therapeutically effective amount of at least one member selected from the group consisting of Serpens spp. HBL-112 bacteria and Serpens spp, HBL-112 bacterin in combination with a veterinarally acceptable diluent or a carrier.
 3. A method for preventing Papillomatous Digital Dermatitis in ruminants comprising administering to a ruminant a therapeutically effective amount of at least one member selected from the group consisting of Serpens spp. HBL-112 bacteria and Serpens spp. HBL-112 bacterin sufficient to prevent and treat said ruminant, wherein said step of preventing comprises inhibiting wart formation in said ruminant.
 4. A method of treating Papillomatous Digital Dermatitis in ruminants comprising administering to a ruminant in need thereof a therapeutically effective amount of at least one member selected from the group consisting of Serpens spp. HBL-112 bacteria and Serpens spp. HBL-112 bacterin sufficient to prevent and treat said ruminant, wherein said of treating comprises reducing wart size in said ruminant.
 5. The method of claim 4 wherein said ruminant has symptoms of Papillomatous Digital Dermatitis.
 6. The method of claim 4 wherein said ruminant has no symptoms of Papillomatous Digital Dermatitis.
 7. The composition of claim 2 wherein said ruminant has symptoms of Papillomatous Digital Dermatitis.
 8. The composition of claim 2 wherein said ruminant has no symptoms of Papillomatous Digital Dermatitis.
 9. The composition of claim 2 further comprising Serpens flexibilis or Serpens flexibilis bacterin.
 10. The method of claim 3 wherein said ruminant has symptoms of Papillomatous Digital Dermatitis.
 11. The method of claim 3 wherein said ruminant has no symptoms of Papillomatous Digital Dermatitis.
 12. The method of claim 3 further comprising administering Serpens flexibilis or Serpens flexibilis bacterin to said ruminant.
 13. The method of claim 4 further comprising administering Serpens flexibilis or Serpens flexibilis bacterin to said ruminant. 